<?php
if(isset($_GET["sub"]))
{
    echo $_GET["text"];
 if($_GET["text"]=='123')
 {
echo "succeed";
     
 }
    
    
}





?> 
<form action="" method="GET">
    <p> 密码</p> <input type="text" name="password">  
           <input type="submit" name="sub">   
    
</form>